This year marks the 100th anniversary of the start of World War I, the 4-year conflict that cost the lives of millions of soldiers and civilians from all parts of the world.

Starting in 1914, The Great War plunged Europe into darkness, turning parts of the continent into a swamp of death, destruction and misery. Soldiers died by the hundreds of thousands in kilometers-long trenches, bombardments leveled entire cities and towns and thousands were forced to flee their homes or battle hunger and poverty if they remained behind.

One hundred years after the beginning of the war, photographer Peter Macdiarmid revisited some of the key locations of the conflict. He overlaid his pictures with shots taken during the war years, bringing the haunting conflict of 1914 to 1918 back to life.

The town hall and belfry of Arras, France is seen from the main square in this archive photo of destruction wrought during WWI. The date of the photo is unknown, but the belfry was destroyed on October 21, 1914. Medieval tunnels under the city, which were expanded during the war, were pivotal in helping British forces to hold the city.

A large crowd of men respond to a call by the War Office for married men aged between 36 and 40 to become munition workers. They gathered outside the Inquiry Office at Scotland Yard in London, England during World War 1.